A chemical having the general formula R1R2C=NR3, where R3 is an alkyl or an aryl but not a hydrogen, is referred to as a Schiff base in organic chemistry. Depending on their structural makeup, they can be regarded as a subclass of imines and are either secondary ketimines or secondary aldimines. The phrase is frequently used interchangeably with azomethine, which only applies to secondary aldimines (RCH=NR', where R' H). These compounds have a variety of unique naming conventions. For instance, a Schiff base formed from an aniline, where R3 is a phenyl or a modified phenyl, may be referred to as an anil, whereas bis-compounds are sometimes termed salen-type compounds. These substances are typically referred to as Schiff bases when they are utilised as ligands to create coordination complexes with metal ions.